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BY JUSTIN RAY
Follow the countdown and launch of the Lockheed Martin Atlas 2AS rocket with the AMC-11 communications satellite. Reload this page for the very latest on the mission.

WEDNESDAY, MAY 19, 2004
With its retirement looming on the horizon, Lockheed Martin's Atlas 2AS rocket kept its flawless success record alive and well Wednesday with the launch of a broadcasting satellite that will aid the expansion of high-definition TV programming across the United States. Read our full story

Built by Lockheed Martin, AMC-11 will be operated in geostationary orbit by New Jersey-based SES AMERICOM to transmit television programming across the United States when it enters service later this year.

2249 GMT (6:49 p.m. EDT)
T+plus 27 minutes, 15 seconds. the Centaur has completed its maneuver to the proper position for satellite deployment.

2246 GMT (6:46 p.m. EDT)
T+plus 24 minutes, 15 seconds. Ignition and full thrust! The Pratt & Whitney RL10 engines of the Centaur upper stage are firing for the burn to boost the AMC-11 cargo from the current parking orbit to a highly elliptical geosynchronous transfer orbit around Earth.

2244 GMT (6:44 p.m. EDT)
T+plus 22 minutes. This upcoming Centaur firing, scheduled to last just under two minutes in duration, occurs over the Atlantic Ocean between the African Ivory Coast and Ascension Island as the rocket passes over the equator.

2231 GMT (6:31 p.m. EDT)
T+plus 9 minutes, 42 seconds. MECO 1. The Centaur main engines have shut down as planned following the first of two planned firings to propel the AMC-11 spacecraft into the proper orbit. The vehicle will coast for about 15 minutes before the Centaur reignites to propel the satellite into geosynchronous transfer orbit.

2230 GMT (6:30 p.m. EDT)
T+plus 8 minutes, 50 seconds. The rocket is now 977 miles downrange, traveling at 13,300 mph. There is less than a minute remaining in this first firing of the Centaur upper stage to achieve a preliminary parking orbit around Earth.

2227 GMT (6:27 p.m. EDT)
T+plus 5 minutes, 10 seconds. The sustainer engine on Atlas has shut down. And the 82-foot long first stage has been jettisoned from the Centaur upper stage to fall into the ocean below.

2225 GMT (6:25 p.m. EDT)
T+plus 3 minutes, 31 seconds. The payload fairing has been jettisoned. It is no longer needed to protect AMC-11 satellite during flight through the atmosphere.

2224 GMT (6:24 p.m. EDT)
T+plus 2 minutes, 50 seconds. After reaching 5.0 g's of axial acceleration, the booster engines have shut down on the first stage. The bottom section of the rocket containing these two outer engine nozzles was then jettisoned.

Atlas is now in the sustainer solo phase of flight. This is the firing of the center engine of the Atlas vehicle to consume the remaining fuel in the first stage.

2223 GMT (6:23 p.m. EDT)
T+plus 1 minutes, 58 seconds. Having burned all their propellant, the air-lit ATK Thiokol solid rocket boosters have separated from the Atlas rocket. The vehicle is now riding the power of its Rocketdyne MA-5A engine system.

2223 GMT (6:23 p.m. EDT)
T+plus 79 seconds. The two spent ground-started solid rocket boosters have separated from the Atlas 2AS rocket's first stage to fall into the Atlantic Ocean. The two-air lit boosters continue to fire along with the first liquid-fueled engines.

2223 GMT (6:23 p.m. EDT)
T+plus 61 seconds. The two air-lit solid rocket boosters mounted to the Atlas first stage have ignited as the two ground-lit motors burn out. The spent booster casings will be jettisoned in a few moments once the rocket flies within a preset drop zone.

2222 GMT (6:22 p.m. EDT)
T+plus 15 seconds. The Atlas rocket is steadily rising in the late afternoon sky here at Cape Canaveral on the 685,000 pounds of thrust being generated by the liquid-fueled MA-5A main engines and two solid-propellant strap-on boosters.

2222 GMT (6:22 p.m. EDT)
LIFTOFF! Liftoff of Atlas/Centaur-166 and the AMC-11 cable television broadcast spacecraft. And the vehicle has cleared the tower at Complex 36B!

In the next few seconds the liquid hydrogen and liquid oxygen vent valves will be locked and the flight data recorders will be readied. The engine ignition sequence will begin at T-minus 2.4 seconds.

2221 GMT (6:21 p.m. EDT)
T-minus 1 minute. Engines are being verified ready for flight. The final status checks of the propellant and pneumatic systems are upcoming to confirm the Atlas and Centaur stages are "go" for launch.

In the past minute, the inertial navigation unit was launch enabled, liquid hydrogen tanking was secured, fuel tank pressures were reported stable, the solid rocket boosters were armed and the ignition enable switch was closed.

2220 GMT (6:20 p.m. EDT)
T-minus 2 minutes. Pressurization of the Atlas/Centaur vehicle has started. Tanks now being brought to proper pressure levels for flight. Also, the solid rocket booster fire commands have been enabled and the vehicle's inadvertent separation destruct safety system has been armed.

Shortly, the Centaur upper stage will go to internal power and the flight termination system will be armed.

2217 GMT (6:17 p.m. EDT)
T-minus 4 minutes, 30 seconds. The water system is being readied for activation at launch pad 36B. Water will flood the pad to suppress the sound produced at liftoff and protect the ground support systems.

2217 GMT (6:17 p.m. EDT)
T-minus 5 minutes and counting! The final phase of today's countdown has commenced for launch of the Lockheed Martin Atlas 2AS rocket carrying the AMC-11 communications spacecraft. Liftoff is slated for 6:22 p.m. EDT from pad 36B at Cape Canaveral Air Force Station in Florida.

2216 GMT (6:16 p.m. EDT)
Standing by to pick up the countdown in one minute.

Liftoff was delayed 30 minutes because Denver engineers checking a guidance computer for a future Atlas mission experienced a problem. But moments ago, the Cape Canaveral launch team was informed that Denver had isolated the problem to the test and configuration in the laboratory.

2142 GMT (5:42 p.m. EDT)
Now 10 minutes into this 45-minute hold. To recap, liftoff has been pushed back to 6:22 p.m. EDT while engineers review an Atlas guidance computer slated for a future mission.

Lockheed Martin has until 8:46 p.m. EDT this evening to launch the Atlas 2AS rocket and AMC-11 spacecraft or else wait until Thursday.

2132 GMT (5:32 p.m. EDT)
T-minus 5 minutes and holding. Clocks has entered the final planned hold in this afternoon's countdown. The pause, which normally lasts 15 minutes, has been extended by a half-hour to 45 minutes in duration. The extra time will be used by Lockheed Martin engineers in Denver while they perform an evaluation of a guidance computer that will used by a future Atlas mission.

This is not related to an attitude drift reading earlier in today's countdown on this Atlas 2AS rocket. Engineers reported that noisy data and winds caused that reading, which is not a concern for a safe flight tonight.

2127 GMT (5:27 p.m. EDT)
T-minus 10 minutes and counting. Countdown clocks are ticking down to the T-minus 5 minute mark where a 45-minute hold will occur. Liftoff is now targeted for 6:22 p.m. EDT.

2124 GMT (5:24 p.m. EDT)
Launch weather officer Johnny Weems has conducted the final planned pre-launch briefing to managers. All launch weather rules are currently "go" for liftoff and expected to remain that way.

2122 GMT (5:22 p.m. EDT)
A correction to our last report on the 30-minute launch delay. The time will be used by engineers to evaluate testing data on a guidance computer that will be used by an upcoming Atlas rocket launch.

The situation is unrelated the tiny attitude drift noticed earlier in today's countdown with this rocket's computer, which Lockheed Martin says is absolutely no problem for launch.

We apologize for the confusion of the two issues.

2114 GMT (5:14 p.m. EDT)
DELAY. Liftoff is being pushed back to 6:22 p.m. EDT to give engineers time to evaluate data from the rocket's guidance computer. A few minutes ago, the launch team noticed a slight attitude drift from the computer, which engineers reported was not a problem. However, further analysis is underway to verify there are no concerns for flight.

As a result, the upcoming hold at the T-minus 5 minute will be extended from its normal 15-minute duration to 45 minutes.

Lockheed Martin has until 8:46 p.m. EDT to launch the Atlas rocket today.

2041 GMT (4:41 p.m. EDT)
The Atlas liquid oxygen tank has reached the 98 percent level where it is being maintained. Topping to 100 percent will be completed shortly.

2040 GMT (4:40 p.m. EDT)
With the liquid hydrogen system chilldown complete, officials have given the "go" to load the super-chilled fuel into the Centaur upper stage. The cryogenic propellant will be consumed with liquid oxygen by the stage's Pratt & Whitney-made RL10 engines to propel the AMC-11 spacecraft into the targeted geosynchronous transfer orbit today.

2026 GMT (4:26 p.m. EDT)
A check of the local weather reveals that all conditions are currently "go" for liftoff. It is a beautiful afternoon along Florida's east-central coast.

2023 GMT (4:23 p.m. EDT)
The Centaur liquid oxygen tank has reached 95 percent full level where it is being secured. Topping to 100 percent will be completed shortly. As the countdown proceeds, the tank will be replenished to replace the cryogenic liquid oxygen that naturally boils away.

And the "go" has now been given to commence loading of the Atlas first stage liquid oxygen tank.

2018 GMT (4:18 p.m. EDT)
The chilldown conditioning of liquid hydrogen propellant lines at pad 36B is starting to prepare the plumbing for transferring the Minus-423 degree F fuel into the rocket.

Also at this time the door of the Complex 36 Blockhouse is being sealed, protecting the 120-member launch team. The blockhouse is located just 1,400 feet away from the Atlas 2AS rocket at pad 36B, and serves as the control center for the countdown to launch.

2016 GMT (4:16 p.m. EDT)
The Centaur liquid oxygen tank is half full.

2011 GMT (4:11 p.m. EDT)
Cryogenic tanking operations are underway at pad 36B this afternoon as the countdown continues smoothly and on schedule for liftoff at 5:52 p.m. EDT. The Centaur liquid oxygen tank is now 10 percent full.

2005 GMT (4:05 p.m. EDT)
Chilldown conditioning of the liquid oxygen transfer lines at pad 36B is complete. And the "go" has now been given to start filling the Centaur upper stage with its supply of super-cold cryogenic oxidizer.

The liquid oxygen -- chilled to Minus-298 degrees F -- will be consumed during the launch by the Centaur's twin RL10 engines along with liquid hydrogen to be pumped into the stage later in the countdown.

1954 GMT (3:54 p.m. EDT)
Safety officials have confirmed that the danger area around the launch pad is cleared of all personnel. This allows the "chilldown" procedure to start for thermal conditioning of the liquid oxygen fuel lines at pad 36B in advance of loading the Centaur upper stage.

Also at this time, the Centaur pneumatic bottle charging and the engine gaseous helium chilldown operations are starting.

The countdown will continue to T-minus 5 minutes where a planned 15-minute built-in hold is scheduled. Launch of the Atlas 2AS rocket with the AMC-11 satellite is expected two hours from now at 5:52 p.m. EDT.

1948 GMT (3:48 p.m. EDT)
No problems were reported during the pre-fueling poll by launch conductor Ed Christiansen. Launch director Adrian Laffitte then gave a "ready" status. Cryogenic liquid oxygen and liquid hydrogen propellants will be pumped into the Atlas and Centaur stages shortly.

At launch pad 36B, workers have completed securing work following mobile service tower rollback. Christiansen has instructed them to clear the area.

1937 GMT (3:37 p.m. EDT)
Now half-way through this built-in hold in the countdown. Lockheed Martin is still targeting an on-time liftoff of the Atlas rocket at 5:52 p.m. EDT from pad 36B at Cape Canaveral.

In about 10 minutes, a readiness check of the launch team for fueling the rocket will be performed by Lockheed Martin launch conductor Ed Christiansen.

The count has 45 minutes of holds scheduled over the course the afternoon that will lead to liftoff at 5:52 p.m. EDT (2152 GMT). A second and final hold is planned at T-minus 5 minutes for 15 minutes. The holds are designed to give the launch team a window of time to work any problems that could arise.

With the mobile service tower rolled back, the final securing of the launch complex is being performed before workers clear the pad. The hazardous operation of loading cryogenic propellants into the vehicle will begin after the countdown resumes at 3:52 p.m.

1920 GMT (3:20 p.m. EDT)
Crews have completed the launch pad final checks, confirming that systems are properly configured. Standing by to enter the built-in hold in two minutes.

1917 GMT (3:17 p.m. EDT)
The flight hazard area roadblocks are being established at this time. And at pad 36B, the final checks are underway before crews depart for launch.

1916 GMT (3:16 p.m. EDT)
The Air Force says there are no Collision Avoidance periods, or COLAs, that would prohibit liftoff during today's launch window. COLA cutouts occur to ensure the rocket isn't launched on a course that would take it too close to an object already orbiting in space.

1859 GMT (2:59 p.m. EDT)
The mobile service tower is now clear of the rocket. The retraction speed is accelerating as the structure rolls to its park location for launch.

1857 GMT (2:57 p.m. EDT)
The launch team has begun the C-band system test. The environmental control final preps and the first stage helium storage preps are starting. Also, the hazardous gas detection system monitoring is beginning.

1852 GMT (2:52 p.m. EDT)
Launch conductor Ed Christiansen has given workers at pad 36B approval to start rolling the mobile service tower away from the Atlas 2AS rocket. Liftoff is now three hours away.

The structure wraps around the rocket, providing access to all areas of the vehicle during its stay on the launch pad. In preparation for fueling and liftoff this evening, the tower is moved a safe distance away, exposing the fully assembled 156-foot tall rocket for the first time.

1847 GMT (2:47 p.m. EDT)
The navigation test on the rocket's Inertial Navigation Unit guidance computer has been completed. The INU final alignment is now underway.

1840 GMT (2:40 p.m. EDT)
Launch team members have been polled to confirm all are "ready" for mobile service tower rollback. The retraction is slated to begin at 5:45 p.m.

The full launch team has been assembled to oversee the final three-and-a-quarter hours of the countdown for today's flight of the Lockheed Martin Atlas-Centaur rocket carrying the AMC-11 cable TV satellite into orbit.

There are two holds, lasting for a total of 45 minutes, built into the countdown at T-minus 105 minutes and T-minus 5 minutes. Liftoff is targeted for 5:52 p.m. EDT.

The countdown is being controlled from the Complex 36 Blockhouse where the 120-member team is positioned at consoles to monitor systems, fuel the rocket and perform final tests leading up to liftoff of this Atlas 2AS vehicle. The senior management team is housed in the Atlas 5 Spaceflight Operations Center (ASOC) at Complex 41.

1814 GMT (2:14 p.m. EDT)
Safety teams have completed the so-called holdfire checks to verify the countdown can be halted at the last moment. Meanwhile, launch pad workers are finishing activities to configure Complex 36 and prep the mobile service tower for rollback starting at 2:52 p.m.

1727 GMT (1:27 p.m. EDT)
The spacecraft RF link checks have been completed and the Centaur upper stage helium purges are starting as the countdown continues at pad 36B. The formal portion of the countdown begins just over an hour from now at 2:37 p.m. EDT.